The present invention relates to such a receiving device applied to a television that receives a digital broadcast, especially a digital broadcast according to the Advanced Television Standards Committee (ATSC) standard.
There has conventionally been a television available for receiving a program on the air. As well known, each broadcasting station is assigned a carrier wave frequency used in broadcasting of programs. A television is capable of selecting a program to be received by switching a channel.
The television, however, has some channels through which no programs are broadcast among the channels capable of reception therethrough. The television capable of selecting such a channel through which no program is broadcast is troublesome in channel selection by a user. To guard against it, there is such a proposal that the channels through which no program is broadcast should not be selected when the user selects his desired program.
Specifically, such a television is proposed that has a function (which is called an automatic storage function here) whereby all the channels capable of reception therethrough are detected beforehand on whether any program is broadcast through them, so that subsequently a channel map which registers therein only the channels through which a program is broadcast is created and stored, thus inhibiting the selection of a channel not registered in the channel map in usual time.
To create the channel map using this automatic storage function, however, it is necessary to detect all of the channels capable of reception therethrough on whether any program is broadcast therethrough, so that it takes long time to create the channel map. In particular, recently, an increasing number of channels can be accommodated in reception by the device, thus leading to a demand for reduction in time for execution of the automatic storage function.
Japanese Unexamined Patent Publication No. 6-204804 proposes therein a device for selecting only such channels that are specified. Channel selection here refers to such an operation that adjusts the reception state at the receiver into the best condition. This technology, however, does not reduce the time for execution of the automatic storage function.
By digital broadcasting according to the Advanced Television Standards Committee (ATSC) standard, one channel is capable of broadcasting a plurality of programs therethrough at a time. As the number of viewable programs increases, the range of selecting programs by the user expands but, at the same time, there would be such a program (channel) that is not desired in viewing by the user. As the programs increase, the channel selection operation for programs to be viewed becomes troublesome. To solve this problem, there is such a proposal that would inhibit the selection of channels not desired in viewing by the user (see Japanese Unexamined Patent Publication No. 5-275977 and Japanese Examined Patent Publication No. 6-81061).